Re: [RFC] schedutil: Fix iowait boost issues for slow I/O devices

From: Peter Zijlstra
Date: Fri Jun 18 2021 - 04:36:25 EST



Aside from everything else:

On Fri, Jun 18, 2021 at 12:06:39AM -0400, Joel Fernandes (Google) wrote:

> +unsigned int sysctl_iowait_reset_ticks = 20;
> +unsigned int sysctl_iowait_apply_ticks = 10;

Never expose HZ to userspace. we even have USER_HZ (no new usage please)
that fixed existing problems with that.

If you expose a knob, make it in sane time units and convert internally
to whatever you need. That said; less is more with knobs.